As a control device that controls a drive device for a vehicle as a controlled object as described above, for example, a device described in Japanese Patent Application Publication No. 2010-030486 (JP 2010-030486 A) (Patent Document 1) is already known. This control device is structured to be capable of performing slip rotational speed control such that an engagement device (second clutch CL2 in Patent Document 1) provided between a rotary electric machine and wheels is brought into a slipping engaged state, and the rotational speed of the rotary electric machine approaches a target rotational speed. In this case, the target rotational speed is set to a sum of a synchronous rotational speed (transmission input rotational speed in Patent Document 1) and a target slip rotational speed. The synchronous rotational speed corresponds to a rotational speed of a speed change input shaft or the rotary electric machine when the engagement device is in a directly coupled engaged state.
A situation is conceivable in which, for example, a device (such as a hydraulic pressure control device) for controlling an engagement pressure of the engagement device does not operate as commanded, so that the engagement device that should be controlled so as to be in the slipping engaged state is brought into the directly coupled engaged state, differently from the command. If such a situation occurs during the execution of the slip rotational speed control described above, the slip rotational speed control is performed in which the target rotational speed is set to the sum of the synchronous rotational speed and the target slip rotational speed while the rotational speed of the rotary electric machine is limited to the synchronous rotational speed. In this state, the slip rotational speed control cannot appropriately be performed, so a largely fluctuating driving force may be transmitted to the wheels. However, Patent Document 1 does not particularly take note of this.